Effect of diisocyanates as compatibilizer on the properties of ramie/poly(lactic acid) (PLA) composites

Ramie/PLA composites with the diisocyanates as compatibilizer were fabricated by extrusion and injection molding. The influence of different diisocyanates and various diisocyanate content on the mechanical properties and thermal properties of the composites was investigated. The presence of the diisocyanates in the composites lead to the improvements in mechanical properties and thermal properties of the composites. The morphologies of fracture surface using scanning electron microscopy (SEM) provided evidence of improved interfacial adhesion between ramie and PLA from the addition of the diisocyanates. The composites containing isophorone diisocyanate (IPDI) showed the best mechanical properties. The comparison of various IPDI content showed that the composites with 1.5% IPDI could get the optimum mechanical properties, and the excess diisocyanate content resulted in the decrease in the mechanical properties of the composites. However, IPDI content had almost no effect on the crystallization and melting behavior of the ramie/PLA composites.